Mobile communications have quickly developed, and have since 2011 been combine with content service. Likewise, flexible displays are anticipated to become a novel trend in the next generation of displays. Major IT companies are replacing thick, heavy, and easily broken glass substrates with non-glass (e.g. light-weight and flexible plastic) substrates. In addition, active full-color TFT display panels are being developed too. While flat displays are desirable in smartphones and tablets, the product's design should meet the requirements of having thin profile and light weight. Another new development is flexible/soft display technology, which may open a new age of display design. While the mass production of medium or small panels has matured, flexible displays can possibly be mass produced to be lightweight, thin, and having a larger cell space.
Fabrication processes for flexible layers are classified into batch type and roll-to-roll type. A conventional apparatus for TFT devices can be utilized to fabricate TFT devices of the batch type. However, development of substrate-transfer and film-separation techniques is required for the batch type to transfer the flexible display from glass substrates to other plastic substrates, or directly take the flexible display from the glass substrates. The roll-to-roll type needs new apparatuses, and some problems caused by rolling and contact must be overcome.
If the batch type is selected to fabricate TFT devices such as LTPS, high-temperature resistant material will be necessary due to the high process temperature (higher than 400° C.). Because the batch type may utilize the existing apparatuses for glass substrates, apparatus cost can be saved. However, to prevent the peeling of the flexible layer on the glass during the device processes, and easily take out the flexible layer (without adhering on the glass) after the device processes will be major critical points.
Accordingly, a novel substrate structure for manufacturing flexible electronic devices is called for.